We study multi-rate peer-to-peer video conferencing applications, where the participants are limited by their uplink and downlink constraints. In order to maximize the system-wide video quality in the video conference session, the peers are allowed to receive the videos at different rates using scalable video coding. One of the many challenges introduced in this setting is to determine the structure of the content distribution trees and then optimizing their rates, while staying within the tight delay constraints of the real-time conferencing application. Towards this end, we first consider a single source setting, where the video quality is modeled as a concave utility function of the bit-rate and the number of distribution trees grows quadratically in the number of receivers. We then propose a simple algorithm based on progressive filling that finds an optimal rate distribution vector.

Speaker 2: Oner Orhan [Advisor: Prof. Elza Erkip]

“Throughput Maximization for an Energy Harvesting Communication System with Processing Cost” (Download Presentation)

In wireless networks, energy consumed for communication includes both the transmission and the processing energy. In this paper, point-to-point communication over a fading channel with an energy harvesting transmitter is studied considering jointly the energy costs of transmission and processing. Under the assumption of known energy arrival and fading proﬁles, optimal transmission policy for throughput maximization is investigated. Assuming that the transmitter has sufﬁcient amount of data in its buffer at the beginning of the transmission period, the average throughput by a given deadline is maximized. Furthermore, a “directional glue pouring algorithm” that computes the optimal transmission policy is described.